Recently, a housing is often formed by using a carbon-fiber-reinforced resin base plate from the viewpoint of achieving weight and thickness reduction. However, it is difficult to provide a complex mechanical section such as ribs on the carbon-fiber-reinforced resin base plate and to form a high standing wall on the base plate. Therefore, a housing formed by performing outsert molding of a frame of synthetic resin around the carbon-fiber-reinforced resin base plate of a flat plate shape is known. In this case, from the viewpoint of improving stiffness of the housing, an area of use of the carbon-fiber-reinforced resin base plate should preferably be as large as possible.
In addition, from the viewpoint of improving the stiffness of the housing, a resin portion to be formed into the frame of the carbon-fiber-reinforced resin base plate should preferably have an incurved C-shaped cross-section. The frame portion having the C-shaped cross-section is formed by providing a mold with sliders that are moved along the carbon-fiber-reinforced resin base plate inside and outside the housing.
If the carbon-fiber-reinforced resin base plate is extended to the frame of the housing, however, edges of the sliders may correspond to the outer edge of the base plate. In this case, a place to provide an inlet through which molten resin is injected cannot be secured due to design.